Scientists puzzled by “Ground hum” from the depths of the ocean

In the Indian ocean recorded a constant sound wave frequency from 2.9 to 4.5 millihertz.

Geophysics using bottom seismographs recorded the acoustic anomalies caused by free oscillations of the ocean floor. A study published in the journal Geophysical Research Letters, reports RIA Novosti.

Their hearing was ten thousand times below the minimum threshold of perception of the human ear. The first time a similar phenomenon was documented in 1998, but still remains unclear the cause of its occurrence. The specialists underline that the “rumble” occurs even at zero seismic activity.

New data were obtained by a team of scientists from France and Germany, led by Martha Dean of the Paris Institute of physics of the Earth. Geophysicists have studied the fluctuations of the bottom of the Indian ocean at two points on the depth and 4540 4260 meters and recorded a constant sound wave frequency from 2.9 to 4.5 millihertz.

The study also presents several hypotheses partially explain the phenomenon. So, scientists suggest that the “hum” can arise either due to the acoustic resonance between the atmosphere and the earth’s crust, or the interactions of solid surfaces with ocean waves.

As reported Корреспондент.netpreviously scientists call the amount of water in the giant underground ocean of our planet.